[FEATURE ADD] Add weighting to metrics

[HunterAP23]

Describe the feature that is being tested/implemented
Add weighting to the different metrics.

• Metrics include (from highest to lowest weight importance)
  • VMAF score
  • MS-SSIM
  • SSIM
  • Encode time
  • Output file size (only when not targeting specific file sizes / bit rates)
  • PSNR
• Allow weights for each metric to be user-configurable or turned off completely

List any relations to other issues in this repository or in other repositories
Provide a list of issues.